In a band saw for cutting a workpiece provided are saw band guiding devices that direct and movably guide tooth tips of a saw band provided at the band saw in a direction of cutting the workpiece. Each of the aforementioned saw band guiding devices is comprised of a fixed insert holder, unitarily at a tip end portion thereof, comprising a fixed insert guide for guiding one side surface of the saw band. Further a movable insert holder, at a tip end portion thereof, comprising a movable insert guide for guiding another side surface of the saw band, which is opposed to the fixed insert guide, is movably (rockably) provided at the fixed insert holder. The interval size between the fixed insert guide and the movable insert guide is provided to be capable of being regulated according to the thickness of the saw band (see the PTL 1 for example).